| 摘要 |
PURPOSE:To make the time for preparation for battery exchange definite and to exchange batteries economically by detecting the voltage of the battery with a voltage detector and displaying the display signal for the voltage drop on a liquid crystal display when the detected voltage is lower than a specified value. CONSTITUTION:When the bottom plates 12, 13 in the contact parts 14, 15 of a level 9 for tracks which is subjected to zero adjustment are brought into contact with the top surfaces of rails and an electric power source switch 27 is closed, a level detector 18 outputs the signal of the level and cant of the tracks. The outputs thereof are inputted through a low pass filter 21 to a differential amplifier 22, by which the difference thereof from the input from a zero adjuster 20 is determined. The result is displayed digitally on a liquid crystal display 25 through an AD converter 23 and a decoder 24. When a measuring switch 42 is changed over, the output of a constant voltage device (battery) is displayed digitally on the display 25 through the converter 23 and the decoder 24. When said voltage drops to a specified value or below, a display symbol is displayed and the time for exchanging the battery is indicated. The battery is thus exchanged economically. |
